Transferring apparatus and large transferring apparatus

ABSTRACT

A transferring apparatus is composed of a first arm swingably provided around a first axis of a pedestal, a second arm whose length is different to the first arm is swingably provided around a second axis, a hand attached to the front end of the second arm, and a first motor to reciprocatingly swings the first arm provided in the pedestal. A first pinion is fixed to the pedestal concentrically to the first shaft, and a second pinion is fixed to the base end of the second arm concentrically with the second axis. Further, racks are provided in the both of left and right side of the first pinion and the second pinion. A large transferring apparatus is composed so that two transferring apparatus are arranged in one pair, the hand are mutually coupled by a transfer beam.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. §119 to JapanesePatent Application No. 2007-298713 filed on Nov. 16, 2007. The contentof the application is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to a transferring apparatus, particularly to atransferring apparatus used for supplying and retrieving asemi-processed work to and from a pressing machine or stamping machine,and to a large transferring apparatus using two transferring apparatuseswhich transfer a large work by holding with more than two places spacedwidely.

BACKGROUND OF THE INVENTION

Japanese Published Patent Application No. S52-121262 (“JP '262”), thearm operating apparatus of the robot of joint type is disclosed. In thisapparatus, the first arm is rotatably attached to a pedestal, and thesecond arm whose length is same as the first arm is rotatably coupled tothe front end of the first arm. The belt is wrapped between the firstpulley fixed to the pedestal and the second pulley fixed to the base endof the second arm. The diameter of the second pulley is made to be ½ ofthe diameter of the first pulley. The first arm swings reciprocatinglyby a motor. Therefore, by driving the motor reciprocatingly, the firstarm swings and the second arm also swings as the same angle as the firstarm synchronized with the first arm through the pulley and the belt.Resultantly, the grip portion attached to the front end of the secondarm operates reciprocatingly in liner motion.

Further, in JP '262, the apparatus to parallely move the grip portion isdisclosed. In this apparatus, the belt is wrapped between a fixed pulleyfixed to the pedestal, and the intermediate pulley which is concentricwith the second pulley and which has the same diameter as the firstpulley. The driven pulley of the same diameter as the intermediatepulley, is fixed to the grip portion. The belt is wrapped between theintermediate pulley and the driven pulley.

In Japanese Published Patent Application No. H06-143183 (“JP '183”), thehandling robot having the first arm and the second arm which are aboutsame as those of JP '262 is disclosed. In this robot, the pedestal isrotated horizontally, and the grip portion is rotated by a motorattached to the joint portion of the second arm and the first armthrough the pulley and the belt.

Japanese Published Patent Application No. 2000-233393 (“JP '393”), thework retrieving apparatus having the first arm and the second arm whichare about same as JP '262 is disclosed. In this apparatus, the first armis rotated or driven by the first motor attached to a pedestal, and thesecond arm is rotated by a second motor through the pulley and the belt.In this, the chuck portion (grip portion) attached to the front end ofthe second arm can be moved to the arbitrary position in a verticalplane and with arbitrary trajectory by two axis control. The two axiscontrol can independently rotate the first arm and the second arm. Forexample, it can be moved up and down to retrieve the molded object fromthe extrusion molding machine, and it can move the object horizontallyto a predetermined position. The length of the first arm and the secondarm may be not identical.

Japanese Published Patent Application No. 2002-66976 (“JP '976”), thevacuum robot for transferring substrates which is about same as JP '393in the point that the first arm and the second arm are made to operateindependently, is disclosed. And, in Japanese Published PatentApplication No. 2005-238381 (“JP '381”), the transferring apparatus ofhorizontal revolution type which is about same as JP '183 is disclosed.The apparatus has a tilt mechanism to be capable of controlling theangle of a hand independently to a second arm.

In Japanese Published Patent Application No. 2005-161406 (“JP '406”),the work transferring apparatus in the tandem press line is disclosed.This apparatus has a pair of beam installed between adjacent pressmachines; the carrier running along the beam; the swinging tableswingably hanged to the carrier and being swingingly driven; the feedlever provided by the swinging table through the linear moving mechanism(extend/retract mechanism). In this work transferring apparatus,lengthwise or longitudinal movement of back and fourth of the carrier,back and fourth swing of the swinging table, the extension andretraction of the feed lever are independently operated. And theseoperations are combined to carry out the work transfer between thepressing machines of the tandem press line. Stated differently, byswinging the swing table while the carriers move between the pressingmachines, and extending and retracting the feed lever tune with theswing, the up and down movement to retrieve the work, the forwardmovement to the next press machine, the up and down movement to releasethe work, the backward movement to retrieve the next work aresequentially be carried out.

Further in JP '406, the arm equipped with the vacuum cup is furtherprovided swingably at the front end of the feed lever extending andretarecting from the swinging table. Moreover, the transferringapparatus for large machines is disclosed, in which the worktransferring apparatuses provided as the pair in left and right, supportthe cross bar extending left and right, and the vacuum cup provided inthe cross bar holds the work.

The apparatus of JP '262 has a merit that while having a joint typestructure suitable for transferring a comparatively heavy work, it cantransfer the work linearly. However, the length of the first arm and thelength of the second arm are identical, it is necessary to adapt theheight of the pedestal to the transfer level. Hence, in the case oftransferring at a level higher than the floor, it is necessary to adaptthe height of the pedestal of the robot to the transfer level, such asin the case that the installed position of the pedestal and the mountedposition of the work, for example, the pressing die is different. Thisis same for the handling robot of JP '183, even if the first arm and thesecond arm are changed so as to turn around a horizontal axis to make itsuitable for the transfer of a heavy load.

The product retrieving apparatus of JP '393 is that which independentlycontrols a first arm and a second arm. In this, even if the point thatthe length of the arms is not identical can be applied to the apparatusof JP '262 in which the arms are synchronously swung. It cannot performlinear transfer if nothing is done. This is also same for the JP '976.Moreover, in the transferring apparatus of JP '381, the length of thefirst arm and the second arm is equal (see paragraph [0014]).

The work transferring apparatus of JP '406 performs up and down movementand forward and backward movement by combining the swinging of aswinging table. Therefore, the linear movement (extend/retract) of afeed arm is achieved, but it needs a large stroke in the linear movementmechanism, making it unsuitable for high speed transfer.

This invention is directed to provide a transferring apparatus which cantransfer a work at high speed about linearly by synchronizingmechanically a first arm and a second arm which are rotatably coupled.Further, this invention is directed secondly to provide a largetransferring apparatus suitable for a heavy load using this transferringapparatus.

SUMMARY OF THE INVENTION

A transferring apparatus of this invention is composed of a pedestalhaving a first axis, a first arm having a base end and a front end, asecond arm having a length different to the first arm and having a baseend and a front end, a hand attached to the front end of the second arm,and a drive means to swing the first arm reciprocatingly. The first armis swingably provided around the first axis, and the front end isequipped with a second axis parallel with the first axis. The second armis swingably provided around the second axis. The transferring apparatusfurther has a first circular plate having a center and a periphery, asecond circular plate having a center and a periphery, and a torquetransmission means interposed between the periphery of the firstcircular plate and the periphery of the second circular plate. The firstcircular plate is attached to the pedestal, and the center is within thefirst axis. The second circular plate attached to the base end of thesecond arm, and the center is within the second axis. The torquetransmission swings the second arm synchronously with the first arm.Further, in the transferring apparatus, a ratio of a diameter of thefirst circular plate and a diameter of the second circular plate is setso that the front end of the second arm moves about linearly when thesecond arm swings synchronously with the first arm.

In such transferring apparatus, an angle adjusting mechanism of thesecond arm can adjust the angle of the first circular plate. Further, aparallel movement mechanism can be included, which maintains the hand ata predetermined angle always with respect to a rest frame regardless ofthe turn of the first arm.

Another aspect of this invention comprises a pedestal having a firstaxis, a first arm having a base end and a front end, a second arm havinga base end and a front end, a third arm having a front end, a handattached to the front end of the third arm, and a drive means to swingthe first arm reciprocatingly. The first arm is swingably providedaround the first axis, and the front end is equipped a second axisparallel with the first axis. The second arm is swingably providedaround the second axis. The third arm protrudes from the front end ofthe second arm and the third arm performs liner motion against thesecond arm. The second aspect of the transferring apparatus furthercomprises a first circular plate having a center and a periphery, asecond circular plate having a center and a periphery, a torquetransmission means interposed between the periphery of the firstcircular plate and the periphery of the second circular plate, anextend/retract drive means to extend and retract the third arm, and acontrol means to control so that the front end of the third arm movesabout linearly accompanying with a swing of the first arm. The firstcircular plate is attached to the pedestal and the center is within thefirst axis. The second circular plate is attached to the base end of thesecond arm and the center is within the second axis. The torquetransmission swings the second arm synchronously with the first arm.

And, a tilt mechanism to swing the hand around the front end of thesecond arm or the front end of the third arm can be included.

In an embodiment the first circular plate and the second circular plateare pinions, and the torque transmission means is equipped with a rackmeshing with these pinions. In this case, the pair of racks are arrangedat both sides in left and right line connecting the first axis and thesecond axis, and at least one pinion is provided so as to tolerate thevariation of the distance to the other pinion. Further, at the sametime, the one pinion is energized or forced in a departing direction oran approaching direction to the other pinion.

A large transferring apparatus of this invention includes thetransferring apparatus of the above invention arranged as one pair inleft and right of processing machine, a beam to interconnect the handsof these transferring apparatuses, and a work holding means provided inthe beam. In this large transferring apparatus, the first axis and thesecond axis of the left and the right transferring apparatus arearranged concentrically to each other. Further, the first axis and thesecond axis extend perpendicular to the transfer direction of the workand horizontally, and the each left and the right drive means operatessynchronously mutually.

In the transferring apparatus of this invention, since the length of thefirst arm and the second arm is different, it is not necessary to adaptthe pedestal to the transfer line, allowing the installation at asuitable position. Further, because the ratio of the first circularplate and the second circular plate is set to move the front end of thesecond arm about linearly when the second arm swings synchronously withthe first arm, even though the length of the first arm and the secondarm is different. Therefore, it is possible to perform the transfersimilar to the conventional transferring apparatuses.

The transferring apparatus equipped with an angle adjusting mechanism ofthe second arm to adjust the fixed angle of the first circular plate,can tilt the moving trajectory of the hand to a reference position byshifting the phase of the second arm by adjusting the fixed angle.

Moreover, the transferring apparatus can be equipped with a parallelmovement mechanism to maintain the hand at a predetermined angle withrespect to a rest frame regardless of the swing of the first arm. Sincethe posture of a work does not change when the hand moves, the design orthe planning of the hand and the positioning jig etc. are easy.

In another aspect of the transferring apparatus of this invention, sincefundamental movements can be achieved by the joint type first arm andthe joint type second arm, rapid linear movement is possible. Moreover,appearing and disappearing of the third arm from the front end of thesecond arm allow fine movements such as avoiding a pressing die.Further, the transferring apparatus which is equipped with a tiltmechanism swinging the hand to the second arm, can change the angle of awork when in transferring a work and in mounting it on a jig etc. Hence,it is possible to transfer at an angle suitable for transferring, and tomount at an angle suitable for mounting.

The first circular plate and the second circular plate may be pinions,and the torque transmission means may equipped with racks meshing withthese pinions. It can make the torque transmissibility large comparedwith that using a belt. It may be that the rack are arranged at bothside as one pair in left and right of a line connecting the first axisand the second axis, and at least one pinion is provided so as totolerate the variation of the distance to the other pinion, and onepinion is energized in a direction to depart from or to become close tothe other pinion. In this case, it transmits power from the first pinionto the second pinion through the rack in the side without backlash whenthe first arm turns to one direction, and transmits power through theother rack without backlash in its direction when it turns to the otherdirection. Hence, the vibration due to the backlash can be suppressed,when the swing direction of the first arm changes.

In the large transferring apparatus of this invention, the transferringapparatuses arranged as one pair in the left and right of a processingmachine transfer one sheet or one each of work in a coordinated manner,thereby the weight imposed on one apparatus becomes small. Further, theedge portion of a work can be stably held and the load are reduced,therefore the load torque applied to the hand becomes small.

BRIEF DESCRIPTION OF THE FIGURES

Next, the embodiment of the transferring apparatus of this invention isdescribed with reference to the drawings.

FIG. 1 is a side cross section showing an embodiment of the transferringapparatus of this invention.

FIG. 2 a and FIG. 2 b are respectively a simplified front view and afront view showing the working status of the transferring apparatus ofthis invention.

FIG. 3 is a skeleton drawing showing the working status of the arm ofFIG. 1.

FIG. 4 is a front view showing the status in which the second arm onlyis turned from the status of FIG. 2 a.

FIG. 5 is a skeleton drawing showing the working status of the arm fromthe status of FIG. 4.

FIG. 6 a is a front view showing an embodiment of the tilt mechanismrelated to this invention, FIG. 6 b and FIG. 6 c are explanatorydrawings of the working status of the tilt mechanism.

FIG. 7 a is a front view showing the other embodiment of the tiltmechanism related to this invention, FIG. 7 b and FIG. 7 c areexplanatory drawings of the working status of the tilt mechanism.

FIG. 8, FIG. 9, and FIG. 10 are respectively the front view, plan view,and side view showing an embodiment of the large transferring apparatusof this invention.

FIG. 11 a, FIG. 11 b, and FIG. 11 c are respectively outline explanatorydrawings showing the other embodiment of the power transmissionmechanism of the first arm related to this invention.

FIG. 12 a and FIG. 12 b are respectively outline explanatory drawingsshowing further the other embodiment of the power transmission mechanismof the first arm related to this invention.

FIG. 13 a and FIG. 13 b are a front view and a side view showing theembodiment of the extend/retract arm related to the transferringapparatus of this invention.

FIG. 14 a is a back view of the extend/retract arm, FIG. 14 b is a frontview showing the internal structure of the third arm of theextend/retract arm.

FIG. 15 is a front view showing the embodiment of the transferringapparatus equipped with the extend/retract arm of FIG. 13 a.

FIG. 16 is a side view showing the working status of the transferringapparatus.

DETAILED DESCRIPTION OF THE INVENTION

The transferring apparatus 10 shown in FIG. 1 includes a pedestal 11, afirst arm 12 of which the base end is swingably provided to the pedestaland is extended upward in a reference position, a second arm 13 which isprovided swingably in the upper end of the first arm and is extendeddownward in the reference position, a hand 14 attached to the front endof the second arm, and a first motor M1 to reciprocatingly swings thefirst arm 12 to the pedestal 11. In this embodiment, the center J1 (afirst axis) of rotation or swing of the first arm 12 and the center J2(a second axis) of rotation or swing of the second arm 13 are horizontalrespectively and in parallel mutually.

Further this transferring apparatus 10 further has a synchronousswinging mechanism 15 to swing the second arm 13 synchronously with theswing of the first arm 12, as shown in FIG. 2 a. This mechanism 15 isequipped with a first pinion 16 installed so as not to move to thepedestal 11, a second pinion 17 rotatably provided around the secondaxis J2 and fixed to the second arm 13, and one pair of left and rightracks 18, 19 which mesh with those pinions 16, 17 and move up and downalong the first arm 12. But, the racks 18, 19 may be the one of eitherthe left or the right.

In addition, as shown in FIG. 1, the first pinion 16 is attached to thepedestal 11 through a second motor M2 which is a component of a laterdescribed second arm angle adjusting mechanism 20. It does not rotate asfar as the second motor M2 does not rotate. Moreover, in the racks 18,19, teeth 18 a, 19 a are formed in the portion only where meshing withthe pinions 16, 17, and the racks 18, 19 are supported slidably by thefirst arm 12.

And, in this transferring apparatus 10, the length L2 of the second arm13 (the distance between the center J2 of rotation of the second arm andthe hand 14) is shorter than the length L1 of the first arm (thedistance between the first axis J1 and the second axis J2). It is about½ of the length L1 of the first arm 12. And, the diameter D2 of thesecond pinion (the diameter of the pitch circle) is about 9/23 of thediameter D1 of the first pinion 16, which is made to be smaller than ½.

In the transferring apparatus 10 composed as above, when the first motorM1 rotates in one direction, the first arm 12 coupled to the outputshaft of the motor M1 swings as much as angle θ1 clockwise, for example,as shown in FIG. 2 b, around the first axis J1. Additionally, thereference numeral K is a reference line of vertical direction. At thismoment, since the first pinion 16 does not rotate, the one rack 18supported by the first arm 12 descends toward the base end side of thefirst arm 12. And the other rack 19 performs linear movement so as toascend toward the front end side. Accompanying the movement of the racks18, 19 in the opposite direction, the second pinion 17 swingsanti-clockwise until angle θ2 to the vertical line. Additionally thereference numeral 22 is a floor face.

At this moment, the height H of the second arm 13 (The vertical distancebetween the first axis J1 and the hand 14) becomes:

H=L1 cos θ1−L2 cos θ2.

And, if the ratio of the diameter D1/D2 of the first pinion 16 and thesecond pinion 17 is set to i (D1/D2=i), since θ2=iθ1-θ1, it becomes:

H=L1 cos θ1−L2 cos(iθ1−θ1).

The graph of the relation between the height H and the angle θ1 of thefirst arm is shown in FIG. 2 b and FIG. 3. As seen in the figures, thefront end of the second arm 13 moves closer to a horizontal line shownby the chain line P.

If the length of the first arm 12 and the second arm 13 is equal, andthe diameter D2 of the second pinion 17 is ½ of the diameter D1 of thefirst pinion 16, the front end of the second arm 13 moves horizontallystrictly, as the apparatus of JP '262. But since in this transferringapparatus 10, the length of the first arm 12 is about twice of thelength L2 of the second arm, and the ratio of the diameter D1 of thefirst pinion 16 and the diameter D2 of the second pinion 17 is about23/9, the movement of the front end of the second arm does not becomesstrictly horizontal. It deviates from the horizontal line along the way,but it is not much a problem in practice.

Additionally, in order to make the height H, when the angle of the firstarm 12 is θ1, equal to the height L1-L2 in the reference position,stated differently, to make it as L1-L2=L1 cos θ1-L2 cos (iθ1-θ1), it issufficient to make it as i=1+[ cos-1{L1(cos θ1−1)+L2}/L2]/θ1. From thisequation, the suitable ratio of the diameter of the first pinion and thesecond pinion can be calculated, based on the length of the first armand the length of the second arm as well as the final angle θ1.

As described above, in the transferring apparatus 10 of FIG. 1 and FIG.2 a, the length L2 of the second arm 13 is shorted than the length L1 ofthe first arm. But the ratio of the diameter D1 of the first pinion 16and the diameter D2 of the second pinion 17 are suitably selected, asshown in FIG. 2 b and FIG. 3. Therefore, the hand 14 of the front end ofthe second arm 13 can be moved about horizontally. Further, as foundfrom FIG. 2 b, in the status that the first arm 12 is swung large to thereference line K, the second arm 13 swings further large to the verticalstraight line K2. Hence, it is easy for the hand 14 provided in thefront end of the second arm 13 to retrieve a work from or to supply awork to such a narrow place, such as between an upper pressing die and alower pressing die of a press machine. In addition, when the first motorM1 is rotated reversely from the state of FIG. 2 b, it returns to thestate of FIG. 2 a via the same trajectory.

In the case of FIG. 3, the first arm 12 is swung as much as theidentical angle from the reference line to the front side and the backside. By swinging back and forth as thus, a work which is press-workedin the foregoing process of the left edge can be moved to the nextpressing die. But, the swinging angle of first arm 12 is not necessaryto be made identical in the fore and back. Moreover, it can be selectedsuitably according to the shape of the work to be transferred, the jigor the pressing die to retrieve the work, and the jig or the pressingdie of the next process to which the work is supplied.

When the length of the second arm 13 is shortened as described above,even when the pedestal 11 is installed on the floor face 22, the workcan be transferred with the transfer level higher than the floor face.Hence, when the work supplying height (the height of the upper face of apressing die) of the machine is higher than the floor face, it is notnecessary to make the pedestal 11 high. Further, since the second arm 13which is provided at the tip side of the apparatus and which moveslargely, can be made light, thereby the whole inertia becomes small andthe power of the first motor M1 can be made small.

Next, the angle adjusting mechanism 20 of the second arm is describedwith reference to FIG. 1 and FIG. 4. This angle adjusting mechanism 20of the second arm is that in which the second motor M2 is connected tothe first pinion 16 and the second arm 13 only is made to be advanced ordelayed as much as the predetermined angle θ3, while the first arm 12remains stationary. When the phase of the second arm 13 is made to beadvanced as much as θ3 and the first arm 12 is swung by driving thefirst motor M1, the hand 14 of the front end of the second arm 13 movesalong the inclined transfer line as shown by the chain line P2 in FIG.5. Accordingly, in the case that there are obstacles in its way,transfer can be carried out via a path which avoids the interferencewith the obstacles. Inversely, in the case that the transfer is carriedout with its movement being delayed, it becomes a transfer lineinversely inclined, as shown in the imaginary line P3.

Next, the parallel movement mechanism 24 of the hand and the tiltmechanism 25 are described with reference to FIG. 1 and FIG. 6 a. Asshown in FIG. 1 and FIG. 6 a, a first gear 26 is provided concentricallyto the first axis J1. This first gear 26 is coupled to the second gear28 which is provided rotatably concentrically to the second axis J2through a torque transmission mechanism 27. The torque transmissionmechanism 27 comprises semi-circular sector gears 31, 32 providedrotatably around shafts 29, 30 supported respectively by the first arm12, a link 33 coupling those sector gears 31, 32. The link 33 iscomposed of two units which is one pair of the left and the right, butit may be one unit. Moreover, in place of the torque transmissionmechanism 27 of link system, the other torque transmission mechanismsuch as a chain, a pulley, a timing pulley can be adopted.

On the other hand, the hand 14 of the front end of the second arm 13 issupported rotatably in the second arm 13 by a shaft 34. A first timingpulley 35 is coupled to the second gear 28 so as to co-rotate, and asecond timing pulley 36 is fixed to the shaft 34 so as to co-rotate. Thetiming pulleys (geared pulley) 35, 36 are mutually coupled by a timingbelt 37 (geared belt) which is a wrapping connector. The gear ratio ofthe first gear 26 and the second gear 28 is 1, and the gear ratio of thefirst timing pulley 35 and the second timing pulley 36 is also 1.Thereby, the first gear 26, the torque transmission mechanism 27, thesecond gear 28, the first timing pulley 37, and the second timing pulley36 composes a parallel movement mechanism 24 of the hand.

Further in this transferring apparatus 10, a third motor M3 is providedin the pedestal 11. And a drive gear 38 coupled to the output shaft ofthe third motor M3 is meshed with the first gear 26 to constitute a tiltmechanism of the hand.

In the transferring apparatus 10 composed as described above, when thefirst arm 12 is swung as much as angle θ1, while the third motor M3 isstopped, since the first gear 26 remains stationary, the first gear 26turns as much as angle θ1 in the reverse direction to the first arm 12(see FIG. 6 b). The rotation is transmitted to the second gear 28through the torque transmission mechanism 27, and the second gear 28also rotates as much as angle θ1 in the reverse direction to the firstarm 12. Accordingly, the second gear 28 does not rotate with respect tothe rest frame. The motion of the second gear 28 is transmitted to theshaft 34 of the hand 14 through the first timing pulley 35, the timingbelt 37, and the second timing pulley 36. This shaft 34 also does notrotate with respect to the rest frame similar to those described above.Accordingly, even when the second arm 13 swings accompanying the swingof the first arm 12, the hand 14 moves about horizontally maintainingthe original angle (see FIG. 6 b). Thereby, the work held by the hand istransferred with its posture not changing, achieving parallel movementfunction.

When the angle of the work is desired to be changed while retrieving orsupplying a work, the tilt mechanism is used. In other words, when theposition of the first arm is placed in any of the position, the thirdmotor M3 is rotated to rotate the drive gear 38. This rotation istransmitted to the first gear 26, and transmitted to the shaft 34 of thehand 14 through the torque transmission mechanism 27, the second gear28, the first timing pulley 35, the timing belt 37, and the secondtiming pulley 36. And the hand 14 rotates as much as the samepredetermined angle as the first gear 26 (see FIG. 6 c). Thereby, theposture of the work can be changed according to need.

In the parallel movement mechanism and the tilt mechanism of FIG. 6 a,the torque transmission mechanism 27, equipped with two semi-circularsector gears 31, 32, is interposed between the first gear 26 and thesecond gear 28. Hence, it is also possible that the semi-circular sectorgear 26 a in place of the first gear and a rotating link 28 a in placeof the second gear are directly coupled by a link 33. Since it isadvantageous to make the posture of the work constant, the parallelmovement mechanism of FIG. 6 a or FIG. 7 a is usually made to be astandard equipment. But there is a case that the adjustment mechanismand the tilt mechanism of the second arm are not necessary, this isusually made to be an option, because the second motor M2 and the thirdmotor M3 should be added.

Next, the embodiment of the large transferring apparatus of thisinvention is described with reference to FIG. 8 to FIG. 10. In the largetransferring apparatus 40 of FIG. 8, the transferring apparatus 10 ofFIG. 1 is arranged to be one pair in left and right spaced at aninterval, and at the same time, a common transfer beam 41 is used as ahand. A vacuum cup or gripper which actually holds a work is attached tothe beam 41 detachably. And, in this embodiment, the left and the righttransferring apparatus 10 is made to be plane symmetry, and as thepedestal 11, that which is common large one is used. The second armadjusting mechanism and the tilt mechanism are not equipped. The outputshaft 42 of the first motor M1 and the base end of the first arm 12 arecoupled by a drive gear 43 fixed to an output shaft 42 and a driven gear44 fixed to the first arm 12, as shown in FIG. 9.

The motion of the large transferring apparatus 40 is substantially sameas the transferring apparatus 10 of FIG. 1 as shown in FIG. 10. And itcan transfer one relatively large work in cooperation of the left andthe right transferring apparatus 10. In this large transferringapparatus 40 also, the transfer distance can be lengthened by swingingleft and right the first arm 12, same as the case of FIG. 3. Therefore,the tilt angle of the second arm 13 becomes small in the position ofretrieving and supplying the work, and it makes the retrieving andsupplying of the work easy.

In the embodiment described above, the transmission of power from thefirst pinion to the second pinion is done by the racks, but, the powertransmission can be done by a gear train, as shown in FIG. 11 a.Moreover, as shown in FIG. 11 b, it can be done by pulleys 46, 47 and abelt 48, or a timing pulley and a timing belt, further, it can be doneby a sprocket and a chain.

In a first arm 50 of FIG. 11 c, the second pinion 17 is provided in somemeasure movable in the direction of the axis line of the arms to thefirst arm 50, and is energized to the first pinion 16 side by a spring51. In this first arm 50, there is no clearance between the upper sideof the teeth of the left and the right racks 18, 19 and the lower sideof the teeth of the second pinion 17, and the clearance is broughttogether between the lower side of the left and the right racks 18, 19and the upper side of the teeth of the second pinion 17. Further, thereis no clearance between the lower side of the teeth of the left and theright racks 18, 19 and the upper side of the teeth of the first pinion16, and the clearance is brought together between the upper side of theleft and the right racks 18, 19 and the lower side of the teeth of thefirst pinion 16.

For making it easy to understand, considering that the first pinion 16rotates clockwise, the left side of the first pinion 16, the left rack18 and the left side of the second pinion 17 transmits power withoutclearance opposing the given energy, and rotates the second pinion 17clockwise. At this moment, since there are clearances between the lowerside of the teeth of the first pinion 16 and the upper side of the teethof the right rack 19, and between the upper side of the teeth of thesecond pinion 17 and the lower side of the teeth of the right rack 19,the power is not transmitted through the right rack 19. Contrary, whenthe first pinion 16 rotates anti-clockwise, inversely to the abovedescription, the right side of the first pinion 16, the right rack 19,and the right side of the second pinion 17 transmit the power withoutclearance opposing the given energy, and do not transmit the powerthrough the left rack 18.

Since the right and the left racks 18, 19 alternately transmit the powerresponding to the rotating direction of the first pinion 16 as thus,regardless of the rotating direction of the first pinion 16, any of therack and pinion transmits the power without clearance. Accordingly, whenthe direction of rotation of the first pinion 16 changes, in otherwords, the swinging direction of the first arm 50 changes, no backlashis generated. Thereby, the vibration of the second arm is suppressed.This effect is same as the case that the second pinion 17 is energizedin the direction of the front end side of the first arm 50, in otherwords, the opposite side to the first pinion. Moreover, the first pinion16 may be energized in the direction of the second pinion 17 side, or inthe reverse direction. As the energizing means, other than a spring 51,such as a gas spring utilizing an air cylinder can be used.

FIG. 12 a and FIG. 12 b show respectively the mechanism of the otherembodiments which drive without backlash. In a mechanism 53 of FIG. 12a, the racks 18, 19 are meshing with the both sides of the first pinion16 and an intermediate pinion 52. The first pinion 16 is energized tothe intermediate pinion 52 side by energizing means such as a spring 56a, same as the above described embodiment. And, while one pair of theleft and the right idle gears 54, 55 meshes with the intermediate pinion52, the second pinion 17 meshes with those idle gears 54, 55. Further,the left and right idle gears 54, 55 are energized in the direction ofdrawing apart mutually by an energizing means such as a spring 56 b. Inthis mechanism 53 also, when the first pinion 16 rotates clockwise, thepower is transmitted to the second pinion 17 without clearance throughthe left rack 18 and the left idle gear 54. And when it rotatesanti-clockwise, the power is transmitted without clearance through theright rack 19 and the right idle gear 55. Accordingly, same as describedabove, when the swinging direction of the first arm changes, no backlashis generated.

In the mechanism 57 of FIG. 12 b, a driven gear 58 is fixed to the firstarm 12 so as not to rotate. And, the rotation of the drive gear 59,driven by the first motor, transmits the power to the driven gear 58respectively through the left and the right intermediate pinions 60, 61provided rotatably in the first arm 12. In addition, the eachintermediate pinion 60, 61 is fixed so that the large diameter gears 60a, 61 a meshing with the drive gear 59 and the small diameter gears 60b, 61 b meshing with the driven gear 58 are made to corotate.

In this mechanism 57, the direction of the backlash of the drive gear 59and the large diameter gear 60 a, and direction of the backlash of thesmall diameter gear 60 b and the driven gear 58 are determined, so thatthe rotation is transmitted to the driven gear 58 without backlashthrough the left intermediate pinion 60 when the drive gear 59 rotatesin one direction. And the direction of the backlash of the drive gear 59and the large diameter gear 61 a, and the direction of the back lash ofthe small diameter gear 61 b and the driven gear 58 are adjusted so thatthe rotation is transmitted to the driven gear 58 without backlashthrough the right intermediate pinion 61 when the drive gear 59 rotatesin the reverse direction. Therefore, the rotation of the first motor canbe transmitted without backlash in any direction of the rotation, and itsuppresses the vibration even when the swinging direction of the firstarm changes same as the case of FIG. 12 a.

The extend/retract arm 62 shown in FIG. 13 a, FIG. 13 b is equivalent tothe second arm 13 of the transferring apparatus 10 of FIG. 1, FIG. 2,and is provided with an extend/retract mechanism. The extend/retract arm62 is equipped with a rectangular pipe like arm holder 63 attachedrotatably to the first arm 12, and a sliding arm 64 housed slidably tothe arm holder. Considering that the arm holder 63 is the second arm,the sliding arm 64 becomes a third arm provided slidably to the secondarm. As shown in FIG. 15, the shaft 17 a of the second pinion 17 of thefirst arm 12 is fixed to the rear surface side of the upper end of thearm holder 63.

Moreover, as shown in FIG. 13 b, an opening 65 is formed in the side ofthe arm holder 63, and a nut holder 66 fixed to the side of the slidingarm 64 protrudingly from the opening 65. In FIG. 13 b, the nut 66 isomitted for easy understanding. In the side of the arm holder 63, upperand lower brackets 67, 68 are attached, and these brackets 67, 68support a screw shaft 69 rotatably. The upper end of the screw shaft 69is coupled with the output shaft of a fourth motor M4. A nut 70 screwingtogether with the screw shaft 69 is fixed to the nut holder 66. In FIG.13 b, the screw shaft 69 and the fourth motor M4 etc. are also omitted.

In the extend/retract arm 62 composed as thus, when the fourth motor M4rotates in one direction, the screw shaft 69 rotates, the sliding arm 64to which the nut 70 screwing together with the screw shaft descends, andits front end further protrudes from the lower end of the arm holder 63.Thereby, the extend/retract arm 62 extends. However, in this embodiment,the upper portion of the sliding arm 64 always protrudes from the upperend of the arm holder 63, therefore the term “extends” here means thedistance between the turning center of (the second axis J2) of the armholder 63 and the front end of the sliding arm 64 and the substantialwhole length of the extend/retract arm 62 (the length of the sliding arm64) does not change. When the fourth motor M4 rotates in the inversedirection, the sliding arm 64 ascends and its front end moves toward thedirection of withdrawing. Thereby, the extend/retract arm 62 retracts.

The reference numeral 71 of FIG. 13 a is a balance cylinder whichenergizes the sliding arm 64 upward in order to cancel the weight of thesliding arm 64. A spring can be also adopted. As the screw shaft 69 andthe nut 70, in order to reduce the friction torque, it is preferable toadopt a ball screw and a ball nut. The structure of the slide portion ofthe arm holder 63 and the sliding arm 64 is preferable to be composed bya linear motion bearing (linear ball bearing) 72 and a linear motionrail (LM rail) 73 fixed to the sliding arm 64, as shown in FIG. 14 a. Inthis case, to receive the torque of rotational direction, two linearmotion rails 73 are adopted.

In the extend/retract arm 62 of FIG. 14 a, 14 b, the parallel movementmechanism 24 which keeps the hand 14 of FIG. 6 etc. in parallel and thetilt mechanism to drive it from the first arm 12 side can not beprovided. Therefore, an independent tilt mechanism 74 is provided in thesliding arm 64 as shown in FIG. 14 b. This tilt mechanism 74 is composedof a first gear 75 and a second gear 76 rotatably provided in the upperend and the lower end of the sliding arm 64 respectively, a torquetransmission mechanism 77 which transmits torque between the first gear74 and the second gear 76, a fifth motor (reference numeral M5 of FIG.13 b) which rotatively drives the first gear 75, and a hand holder 78coupled with the second gear 76.

The torque transmission mechanism 77 comprises a semicircular sectorgear 79 meshing with the first gear 75, a sector gear 80 meshing withthe second gear 76, and a link 81 to couple these sector gears 79, 80mutually. But, other torque transmission mechanisms such as a pulley anda belt, particularly, a timing pulley and a timing belt, or a sprocketand a chain can also be adopted. Moreover, as the fourth motor M4 andthe fifth motor M5, fluid motors such as air motor or an oil hydraulicmotor can be also adopted for saving the weight.

In the tilt mechanism 74 composed as above, when the fifth motor M5rotates in one direction, the hand holder 78 rotates through the firstgear 75, the torque transmission mechanism 77, and the second gear 76,and it control the tilt of the hand 14 holding a vacuum cup. The controlof the fifth motor M5 can be used to hold the tilt of the hand 14horizantly in response to the angle of the extendable arm 62, namely thetilt of the arm holder 63. Further, the control of the fifth motor M5can also be used to tilt the hand 14 avoiding the interference with thepressing die or a pressing machine.

The transferring apparatus 82 shown in FIG. 15 and FIG. 16 is equippedwith the first arm 12 rotatably provided around the first axis J1 to thepedestal and the extend/retract arm 62 provided rotatably around thesecond axis J2 in the front end of the first arm 12, which are aboutsimilar to FIG. 1. Since the length of the extend/retract arm 62 extendsand retracts freely, as the case of the transferring apparatus 10 ofFIG. 1, the ratio of the length of the first arm 12 and theextend/retract arm 62, and the ratio of the diameter of the first pinion16 and the second pinion 17 are not so important. Hence, For example,the length L3 (the distance between the second axis J2 and the turningaxis J3 of the hand holder) in the state that the extendable arm 62 isretracted is made to be same as the length L1 of the first arm, theratio of the diameter of the first pinion (first sector gear) 16 and thediameter of the second pinion 17 can be made to be 2:1. Moreover, thelength L3 of the extend/retract arm 62 may be made always longer thanthe length L1 of the first arm 12, as shown in FIG. 16. Further, it maybe made shorter in the normal state and may be extended when needed. Inthis case, the length of the extending arm 62 and the first arm 12 mayinstantly become congruent, but fundamentally, it is the differentlength.

In the transferring apparatus 82 of FIG. 15, FIG. 16 also, the torquetransmission can be made by one pair of the left and the right racksbetween the first pinion 16 and the second pinion 17, same as the caseof FIG. 1 and FIG. 2. In FIG. 16, the same diameter intermediate pinion52 provided in the upper portion of the first arm 16 and the second arm17 are coupled by one pair of the left and the right racks not shown inthe figure. The intermediate pinion 52 and the second pinion 17, fixedto the arm holder 63, are coupled through one pair of idle gears 54, 55.The reason that the racks and the idle gears 54, 55 are provided as onepair left and right, is to eliminate the backlash.

In the transferring apparatus 82 composed as described above, when thefirst arm 12 is in the central reference position, the extend/retractarm 62 is retracted, and when the apparatus 82 is in the sate ofretrieving a work in a pressing machine of upstream side (left side ofFIG. 16), the extend/retract arm 62 is extended, as shown in FIG. 16.And, after taking out the work, when it passes the reference position,the extend/retract arm 62 is retracted, and when the apparatus 82 is inthe state of placing a work in a pressing machine of downstream side(right side of FIG. 16), the extend/retract arm 62 is extended again.And, when returning to the reference position, the extend/retract arm 62is retracted. Thereby, to the pressing die of the pressing machine ofupstream side and down stream side shown by the imaginary line, it canapproach from the upper side and can withdraw to the upper direction.Hence, the retrieving of a work from the pressing die and the supply ofa work to the pressing die becomes smooth. In the case that there is anobstacle near the pressing die, as shown by the reference numeral 83 ofFIG. 16, it is possible to overgo the obstacle by partially raising thetrajectory of movement of the hand 14. Particularly while it holds awork, the moving trajectory of the hand 14 is selected so that the workdoes not interfere with the pressing die etc.

The first motor M1 to turn the first arm 12 and the fourth motor M4 tomove the sliding arm 64 are computer-controlled so as to realize theabove described two dimensional trajectory. Moreover, the rotation ofthe fifth motor M5 of the tilt mechanism 74 of FIG. 14 b is controlledso as to be electrically synchronized with the swing of the first arm12. However, the fundamental motion of the transfer is based on theswing of the first arm 12 around the first axis J1 and the turn of thearm holder 63 mechanically coupled to the first arm 12 around the secondaxis J2. Thereby, the small amount of movement of the sliding arm issufficient. Hence, a work can be transferred rapidly and safely,compared with the transferring apparatus of JP '406.

1. A transferring apparatus comprising; a pedestal having a first axis;a first arm having a base end and a front end, the first arm swingablyprovided around the first axis, the front end having a second shaftparallel with the first axis; a second arm having a length different tothe first arm and having a base end and a front end, the second armswingably provided around the second axis; a hand attached to the frontend of the second arm; a drive means to swing the first armreciprocatingly; a first circular plate having a center and a periphery,the first circular plate attached to the pedestal and the center iswithin the first axis; a second circular plate having a center and aperiphery, the second circular plate attached to the base end of thesecond arm and the shaft and the center is within the second axis; and atorque transmission means interposed between the periphery of the firstcircular plate and the periphery of the second circular plate, in whichthe torque transmission swings the second arm synchronously with thefirst arm; wherein a ratio of a diameter of the first circular plate anda diameter of the second circular plate is set so that the front end ofthe second arm moves about linearly when the second arm swingssynchronously with the first arm.
 2. A transferring apparatus accordingto claim 1, further comprising, an angle adjusting mechanism of thesecond arm to adjust an angle of the first circular plate.
 3. Atransferring apparatus according to claim 1, further comprising, aparallel movement mechanism to maintain the hand at a predeterminedangle to a rest frame regardless of a swing of the first arm.
 4. Atransferring apparatus comprising; a pedestal having a first axis; afirst arm having a base end and a front end, the first arm swingablyprovided around the first axis, the front end having a second axis; asecond arm having a base end and a front end, the second arm swingablyprovided around the second axis parallel with the first axis; a thirdarm having a front end, the third arm protruding from the front end ofthe second arm, in which the third arm performs liner motion against thesecond arm; a hand attached to the front end of the third arm; a drivemeans to swing the first arm reciprocatingly; a first circular platehaving a center and a periphery, the first circular plate attached tothe pedestal and the center is within the first axis; a second circularplate having a center and a periphery, the second circular plateattached to the base end of the second arm and the center is within thesecond axis; a torque transmission means interposed between theperiphery of the first circular plate and the periphery of the secondcircular plate, in which the torque transmission swings the second armsynchronously with the first arm; an extend/retract drive means toextend and retract the third arm; a control means to control so that thefront end of the third arm moves about linearly accompanying with aswing of the first arm.
 5. A transferring apparatus according to claim1, further comprising; a tilt mechanism to swing the hand with respectto the second arm or the front end of the third arm.
 6. A transferringapparatus according to claim 1, wherein the first circular plate and thesecond circular plate are pinions, and the torque transmission means isequipped with a rack meshing with the pinions.
 7. A transferringapparatus according to claim 6, wherein the pair of racks are arrangedat both sides in left and right of a line connecting the first axis andthe second axis, and wherein at least one pinion is provided to toleratea variation of a distance to the other pinion, and the one pinion isforced in a departing direction or an approaching direction to the otherpinion.
 8. A large transferring apparatus for transferring a workcomprising; the transferring apparatus according to claim 1 arranged asone pair in left and right of a processing machine, a beam tointerconnect the hands of both transferring apparatuses, and a workholding means provided in the beam, wherein the first axis and thesecond axis of the left and the right transferring apparatus arearranged concentrically to each other, and wherein the first axis andthe second axis extend perpendicular to a transfer direction of the workand horizontally, and each the left and the right drive means operatessynchronously.
 9. A transferring apparatus according to claim 4, furthercomprising; a tilt mechanism to swing the hand with respect to thesecond arm or the front end of the third arm.
 10. A transferringapparatus according to claim 4, wherein the first circular plate and thesecond circular plate are pinions, and the torque transmission means isequipped with a rack meshing with the pinions.
 11. A transferringapparatus according to claim 10, wherein the pair of racks are arrangedat both sides in left and right of a line connecting the first axis andthe second axis, and wherein at least one pinion is provided to toleratea variation of a distance to the other pinion, and the one pinion isforced in a departing direction or an approaching direction to the otherpinion.
 12. A large transferring apparatus for transferring a workcomprising; the transferring apparatus according to claim 4 arranged asone pair in left and right of a processing machine, a beam tointerconnect the hands of both transferring apparatuses, and a workholding means provided in the beam, wherein the first axis and thesecond axis of the left and the right transferring apparatus arearranged concentrically to each other, and wherein the first axis andthe second axis extend perpendicular to a transfer direction of the workand horizontally, and each the left and the right drive means operatessynchronously.